This invention relates to the sawing of lumber by a hand-carried, power-driven saw, and particularly to the sawing of long, heavy pieces of lumber which it would be awkward to feed to a conventional stationary table saw. It is a primary feature that the comparatively light saw is carried to the work and is controlled in its movements by suitable settings relative to the work. The work piece itself will generally be supported substantially horizontally or at least in a substantially straight, flat condition on two or more sawhorses. So long as convenience is served, the sawhorses, rather than the work piece, can be readjusted.
A board or beam on which sawing is required to be done will generally be of right, prismatic form. That is to say, it will be of uniform thickness and uniform width, the top and bottom surfaces being parallel to one another. For illustrative purposes, this may be assumed to be the fact.
Assuming that such a work piece is supported, roughly at least, in a horizontal, straight condition on two or more sawhorses, it may be desired to make any one or more of a wide variety of cuts including any one of the following: (a) a lengthwise cut in a vertical plane at right angles to the top and bottom surfaces of the work piece; (b) a cross-cut in a vertical plane at right angles to the top and bottom surfaces and to the side faces of the work piece; or (c) a diagonal cut at right angles to the top and bottom surfaces of the work piece but at any oblique angle crosswise of the work piece. In all of these instances the saw blade should travel in a vertical plane.
In any one of the above-mentioned directions, beveled instead of square cut surfaces may be desired, in which case the saw blade should desirably be mounted with provision for setting it at a tilted angle to the flat top of the work piece of any indicated value up to at least 45.degree.. To these ends the saw is mounted upon a guiding platform that is adapted to rest upon the top surface of the work piece. The saw is mounted for tilting relative to the platform about an axis extending substantially parallel to the top surface of the work piece, with freedom for controlled movement of the blade in a plane determined by adjusted settings of the kind indicated above.
It is a feature of my novel structure that the ultimate work engaging structure, other than the saw blade itself, is caused during any sawing operation to occupy a fixed position relative to the work piece and to provide a smooth friction-free track for smoothly and accurately controlling the advance of the saw blade in one or more steps in the direction for which it is set.
It is a significant feature that a saw guard, which tilts in unison with the saw and is spring biased forward toward a blade covering position, carries a follower in the plane of the saw that fits into the saw cut rearwardly of the saw blade for stabilizing the saw in the intended cutting plane, thereby obviating binding strains upon the saw and possible objectionable deviations from the intended cutting plane.
The saw guard is yieldably biased to turn toward the work piece and in the direction the saw is moved to make a cut, so that the follower always travels in the slot formed by the saw regardless of whether the saw is being advanced in a slanted or upright attitude.
It is a further feature that provision is made for tilting the blade to make bevel cuts up to forty-five degrees, about a tilt axis so located that a desired depth of blade penetration will be achieved regardless of the tilt of the blade. Penetration of the saw for the full thickness of the work piece will be assured.
Adjustment of the tilt angle of the saw blade relative to the work piece shifts the point at which the blade intersects the work piece a distance laterally of a line guide on the sawhorse and may cause the user to cut along a line spaced laterally from the desired cut line. Indexing notches are provided to indicate the true cut line for various tilt angles.